The hybrid V6 in the 450h model is expected to produce around 340bhp and 270lb ft of torque, hitting 0-62mph in 5.9 seconds and going on to a top speed of 155mph. Official figures are expected to be revealed at next month’s Frankfurt motor show.

Although the launch models will be petrol-only, Lexus is known to be developing a frugal diesel engine for GS variants that will be introduced in 2013.

The company wants the new GS to provide ‘a more engaging driving experience’ than its predecessors. A more aerodynamic body, a wider stance and stiffer structure, a transmission with quicker changes and distinctive engine sound and exhaust note provide the new GS with more driver appeal.

Cornering stability is set to be improved using a wider track, by 40mm at the front and 50mm at the rear, and a completely redesigned rear subframe which accommodates a new multi-link suspension system. Four-wheel steering will help with agility.

Ventilated disc brakes with four-piston aluminium front callipers provide the braking force for the new GS, and an increase in the number of aluminium parts will keep weight down.

This is the first of Lexus range to feature a new spindle grille, which will be a design feature on future vehicles in the company’s fleet. The interior has been subject to an overhaul from the previous GS, with more space for front and rear passengers and nearly 25 per cent more boot space. Bluetooth, DVD, 5.1 surround sound speakers, ten airbags and aircon come as standard.

Options on the new GS include a pre-collision system – which uses an infrared camera to monitor the driver’s eyes and sounds an alarm if they are not looking forwards when a collision appears imminent – night vision, head-up display, blind spot monitor and a lane keep assist system.